ACK-NACK signaling enhancements

ABSTRACT

An ACK-NACK feedback message indicates which code words within a transport block that were received in error. The ACK-NACK message has a variable format based on the number of code words in the transport block and the number of code words received in error.

CROSS REFERENCE TO RELATED APPLICATIONS

The present U.S. Utility patent application claims priority pursuant to35 U.S.C. §120 as a continuation of U.S. Utility application Ser. No.13/686,087, entitled “ACK-NACK Signaling Enhancements”, filed Nov. 27,2012, pending, which claims priority pursuant to 35 U.S.C. §119(e) toU.S. Provisional Application No. 61/614,251, entitled “ACK-NACKSignaling Enhancements”, filed Mar. 22, 2012, and U.S. ProvisionalApplication No. 61/727,429, entitled “ACK-NACK Signaling Enhancements”,filed Nov. 16, 2012, all of which are hereby incorporated herein byreference in their entireties and made part of the present U.S. Utilitypatent application for all purposes.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The invention relates generally to signaling within a communicationnetwork and more particularly to ACK-NACK signaling within acommunication network.

2. Description of Related Art

In Long Term Evolution (LTE) and other 4G wireless communicationsystems, each data packet to be conveyed to the receiver (also referredto herein as “destination device”) is made up of multiple code words,which are transmitted to the receiver in a transport block. Each codeword may be provided with individual Cyclic Redundancy Check (CRC) bitsand each transport block may also be provided with overall CRC bitscovering all code words in the transport block.

In the existing Acknowledgment-Negative Acknowledgment (ACK-NACK)signaling, the receiver returns the overall CRC status and not theindividual code word's CRC status. The transport block's ACK-NACKfeedback includes only a single bit in order to minimize bandwidthrequirements. However, this single bit is coded heavily to ensure thatthe feedback information is received by the transmitter (also referredto herein as “source device”) without any error even at very lowsignal-to noise ratios (SNRs). For example, in UTE, the transportblock's ACK-NACK after encoding may occupy about 5% of the symbolresources.

If the ACK-NACK feedback was extended to include the individual codeword CRC status, each code word's ACK-NACK bit would have to be stronglycoded. For example, if the number of code words in a transport block is10, the number of resources to be used for ACK-NACK feedback would haveto be increased by 10 times. In order to accommodate such a requirement,the control channel allocation would have to be increased, resulting inan inefficient usage of the bandwidth.

However, since only the overall CRC status is returned, if the receiveris unable to decode one or more of the code words in the transportblock, the receiver must request retransmission of the entire transportblock. For example, if the receiver is able to decode all of the codewords in a transport block except one, since the transmitter is unawareof which code word was received in error, the transmitter wouldretransmit all of the code words in the transport block. From theretransmitted transport block, the receiver would then decode only thefailed code-word.

Thus, the current ACK-NACK signaling does not inform the transmitter ofwhich code words were received in error, so that the transmitter mayre-transmit only the erroneously received code words. As such, thecurrent ACK-NACK signaling does not efficiently utilize the bandwidthfor ACK-NACK feedback and re-transmission of code words.

BRIEF SUMMARY OF THE INVENTION

The technology described herein is directed to an apparatus and methodsof operation that are further described in the following BriefDescription of the Drawings and the Detailed Description of theInvention. Other features and advantages will become apparent from thefollowing detailed description made with reference to the accompanyingdrawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a system diagram illustrating a portion of a communicationsystem that supports both wired and wireless terminals operatingaccording to embodiments of the present invention;

FIG. 2 is a block diagram functionally illustrating a wireless terminalconstructed according to embodiments of the present invention;

FIG. 3 illustrates transmission of a transport block including multiplecode words from a transmitter (“source device”) to a receiver(“destination device”) according to embodiments of the presentinvention;

FIG. 4 illustrates retransmission of the code words received in errorfrom the transmitter to the receiver according to embodiments of thepresent invention;

FIG. 5 illustrates exemplary ACK-NACK signaling between a source deviceand a destination device according to embodiments of the presentinvention;

FIG. 6 illustrates an exemplary format of an ACK-NACK feedback messageaccording to embodiments of the present invention;

FIG. 7 illustrates exemplary bit patterns of a portion of the ACK-NACKfeedback message of FIG. 6 according to embodiments of the presentinvention;

FIG. 8 illustrates another exemplary format of an ACK-NACK feedbackmessage according to embodiments of the present invention; and

FIG. 9 illustrates an exemplary ACK-NACK signaling method according toembodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a system diagram illustrating a portion of a communicationsystem 100 that supports both wired and wireless terminals operatingaccording to the present invention. The communication system 100includes a Public Switched Telephone Network (PSTN) Interface 101, e.g.,Mobile Switching Center, a wireless network packet data network 102 thatincludes GPRS Support Nodes, EDGE Support Nodes, WCDMA Support Nodes,and other components, Radio Network Controllers/Base Station Controllers(RNC/BSCs) 152 and 154, and Base Stations/Node Bs 103, 104, 105, and106. The wireless network packet data network 102 couples to additionalprivate and public packet data networks 114, e.g., the Internet, WANs,LANs, etc. A conventional voice terminal 121 couples to the PSTN 110. AVoice over Internet Protocol (VoIP) terminal 123 and a personal computer125 couple to the Internet/WAN 114. The PSTN Interface 101 couples tothe PSTN 110. Of course, this particular structure may vary from systemto system.

Each of the Base Stations/Node Bs 103-106 services a cell/set of sectorswithin which it supports wireless communications. Wireless links thatinclude both forward link components and reverse link components supportwireless communications between the base stations and their servicedwireless terminals. These wireless links support digital datacommunications, VoIP communications, and other digital multimediacommunications. The communication system 100 may also be backwardcompatible in supporting analog operations as well. The communicationsystem 100 supports one or more of the Long Term Evolution (LTE)standard, LTE-Advanced (LTE-A) standard, Mobile WiMAX standard,WirelessMAN-Advanced standard, UMTS/WCDMA standards, the Global Systemfor Mobile telecommunications (GSM) standards, the GSM General PacketRadio Service (GPRS) extension to GSM, the Enhanced Data rates for GSM(or Global) Evolution (EDGE) standards, and/or various other OFDMAstandards, CDMA standards, TDMA standards and/or FDMA standards, etc.

Wireless terminals 116, 118, 120, 122, 124, 126, 128, and 130 couple tothe communication system 100 via wireless links with the base stations103-106. As illustrated, wireless terminals may include cellulartelephones 116 and 118, laptop computers 120 and 122, desktop computers124 and 126, and data terminals 128 and 130. However, the cellularwireless communication system 100 supports communications with othertypes of wireless terminals as well. As is generally known, devices suchas laptop computers 120 and 122, desktop computers 124 and 126, dataterminals 128 and 130, and cellular telephones 116 and 118, are enabledto “surf” the Internet 114, transmit and receive data communicationssuch as email, transmit and receive files, and to perform other dataoperations. Many of these data operations have significant downloaddata-rate requirements while the upload data-rate requirements are notas severe. Some or all of the wireless terminals 116-130 are thereforeenabled to support various 4G standards, such as LTE-A andWirelessMAN-Advanced.

FIG. 2 is a schematic block diagram illustrating a wireless terminalthat includes host processing components 202 and an associated radio204. For cellular telephones, the host processing components and theradio 204 are contained within a single housing. In some cellulartelephones, the host processing components 202 and some or all of thecomponents of the radio 204 are formed on a single Integrated Circuit(IC). For personal digital assistants hosts, laptop hosts, and/orpersonal computer hosts, the radio 204 may reside within an expansioncard and, therefore, be housed separately from the host processingcomponents 202. The host processing components 202 include at least aprocessing module 206, memory 208, radio interface 210, an inputinterface 212, and an output interface 214. The processing module 206and memory 208 execute instructions to support host terminal functions.For example, for a cellular telephone host device, the processing module206 performs user interface operations and executes host softwareprograms among other operations.

The radio interface 210 allows data to be received from and sent to theradio 204. For data received from the radio 204 (e.g., inbound data),the radio interface 210 provides the data to the processing module 206for further processing and/or routing to the output interface 214. Theoutput interface 214 provides connectivity to an output display devicesuch as a display, monitor, speakers, et cetera such that the receiveddata may be displayed. The radio interface 210 also provides data fromthe processing module 206 to the radio 204. The processing module 206may receive the outbound data from an input device such as a keyboard,keypad, microphone, et cetera via the input interface 212 or generatethe data itself. For data received via the input interface 212, theprocessing module 206 may perform a corresponding host function on thedata and/or route it to the radio 204 via the radio interface 210.

Radio 204 includes a host interface 220, baseband processing module(baseband processor) 222, analog-to-digital converter 224,filtering/gain module 226, down conversion module 228, low noiseamplifier 230, local oscillation module 232, memory 234,digital-to-analog converter 236, filtering/gain module 238,up-conversion module 240, power amplifier 242, RX filter module 264, TXfilter module 258, TX/RX switch module 260, and antenna 248. Antenna 248may be a single antenna that is shared by transmit and receive paths(half-duplex) or may include separate antennas for the transmit path andreceive path (full-duplex). The antenna may further include multipletransmit and/or receive antennas to support multiple-inputmultiple-output technology. The antenna implementation will depend onthe particular standard to which the wireless communication device iscompliant.

The baseband processing module 222 in combination with operationalinstructions stored in memory 234, execute digital receiver functionsand digital transmitter functions. The digital receiver functionsinclude, but are not limited to, digital intermediate frequency tobaseband conversion, demodulation, constellation demapping,descrambling, and/or decoding. The digital transmitter functionsinclude, but are not limited to, encoding, scrambling, constellationmapping, modulation, and/or digital baseband to IF conversion. Thetransmit and receive functions provided by the baseband processingmodule 222 may be implemented using shared processing devices and/orindividual processing devices. Processing devices may includemicroprocessors, micro-controllers, digital signal processors,microcomputers, central processing units, field programmable gatearrays, programmable logic devices, state machines, logic circuitry,analog circuitry, digital circuitry, and/or any device that manipulatessignals (analog and/or digital) based on operational instructions. Thememory 234 may be a single memory device or a plurality of memorydevices. Such a memory device may be a read-only memory, random accessmemory, volatile memory, non-volatile memory, static memory, dynamicmemory, flash memory, and/or any device that stores digital information.Note that when the baseband processing module 222 implements one or moreof its functions via a state machine, analog circuitry, digitalcircuitry, and/or logic circuitry, the memory storing the correspondingoperational instructions is embedded with the circuitry comprising thestate machine, analog circuitry, digital circuitry, and/or logiccircuitry.

In operation, the radio 204 receives outbound data 250 from the hostprocessing components via the host interface 220. The host interface 220routes the outbound data 250 to the baseband processing module 222,which processes the outbound data 250 in accordance with a particularwireless communication standard (e.g., UMTS/WCDMA, GSM, GPRS, EDGE, etcetera) to produce digital transmission formatted data 252. The digitaltransmission formatted data 252 is a digital base-band signal or adigital low IF signal, where the low IF will be in the frequency rangeof zero to a few kilohertz/megahertz.

The digital-to-analog converter 236 converts the digital transmissionformatted data 252 from the digital domain to the analog domain. Thefiltering/gain module 238 filters and/or adjusts the gain of the analogsignal prior to providing it to the up-conversion module 240. Theup-conversion module 240 directly converts the analog baseband or low IFsignal into an RF signal based on a transmitter local oscillation 254provided by local oscillation module 232. The power amplifier 242amplifies the RF signal to produce outbound RF signal 256, which isfiltered by the TX filter module 258. The TX/RX switch module 260receives the amplified and filtered RF signal from the TX filter module258 and provides the output RF signal 256 signal to the antenna 248,which transmits the outbound RF signal 256 to a targeted device such asa base station 103-106.

The radio 204 also receives an inbound RF signal 262, which wastransmitted by a base station via the antenna 248, the TX/RX switchmodule 260, and the RX filter module 264. The low noise amplifier 230receives inbound RF signal 262 and amplifies the inbound RF signal 262to produce an amplified inbound RF signal. The low noise amplifier 230provides the amplified inbound RF signal to the down conversion module228, which converts the amplified inbound RF signal into an inbound lowIF signal or baseband signal based on a receiver local oscillation 266provided by local oscillation module 232. The down conversion module 228provides the inbound low IF signal (or baseband signal) to thefiltering/gain module 226, which filters and/or adjusts the gain of thesignal before providing it to the analog to digital converter 224. Theanalog-to-digital converter 224 converts the filtered inbound low IFsignal (or baseband signal) from the analog domain to the digital domainto produce digital reception formatted data 268. The baseband processingmodule 222 demodulates, demaps, descrambles, and/or decodes the digitalreception formatted data 268 to recapture inbound data 270 in accordancewith the particular wireless communication standard being implemented byradio 204. The host interface 220 provides the recaptured inbound data270 to the host processing components 202 via the radio interface 210.

Turning now to FIG. 3, in LTE and other 4G wireless communicationsystems, each data packet is transmitted to the receiver in a transportblock 300 made up of multiple code words 310 (CW 1, CW 2 . . . CW n−1,CW n). Each code word 310 includes Cyclic Redundancy Check (CRC) bitsand each transport block 300 may also include overall CRC bits thatapply to all of the code words in the transport block. The receiver usesthe CRC bits to detect errors in the received code words. For example,as shown in FIG. 3, based on the CRC bits for CW 2, the receiver maydetermine that CW 2 is not able to be properly decoded.

In accordance with various embodiments, the receiver provides ACK-NACKfeedback to the transmitter that indicates that CW 2 was received inerror, and therefore, should be retransmitted. As shown in FIG. 4, thetransmitter can then retransmit only CW 2, instead of the entiretransport block, to the receiver to enable the receiver to decode CW 2.

FIG. 5 illustrates an exemplary ACK-NACK signaling between a sourcedevice 500 and a destination device 510. In one embodiment, the sourcedevice 500 and destination device 510 are wireless devices (e.g., thesource device may be a base station and the destination device may be awireless terminal). In another embodiment, one or more of the sourcedevice 500 and destination device 510 may be wired devices.

The source device 500 transmits control information 520 to thedestination device that indicates, for example, the number of code wordsthat will be transmitted in a transport block. The control information520 may also indicate whether the source device 500 will re-transmit allof the code words regardless of the number received in error orre-transmit only the code words received in error. The controlinformation 520 may further indicate the format of ACK-NACK feedbackthat the receiver has to employ (if, for example, multiple feedbackmechanisms are possible).

From the control information 520, the destination device 510 candetermine the format of ACK-NACK feedback messages 530 to be transmittedto the source device 500. For example, if the control information 520indicates that the source device 500 will always re-transmit all codewords, the ACK-NACK feedback message 530 may include only a single bitrepresentative of the overall CRC status of the transport block. Inembodiments in which the control information 520 indicates that thesource device 500 can re-transmit only the code words received in error,the format of the ACK-NACK feedback message 530 can be determined basedon the number of code words within each transport block or otherparameters.

In an exemplary embodiment, to effectively convey to the source device500 which code words were received in error without requiring a separateACK-NACK for each code word, the ACK-NACK feedback message 530 includesa certain number of bits. The minimum number of ACK-NACK bits needed toascertain which code words were received in error can be determinedbased on the number of code words in a transport block (n) and thenumber of code words received in error (m).

For example, the part:{s _(i)}_(i=0) ^(m−1)(1≦s _(i) ≦n,s _(i) <s _(i+1))  (Equation 1)can be computed, which contains the m sorted code word indices that arein error. Then, one can denote:

$\begin{matrix}{\left\langle \begin{matrix}x \\y\end{matrix} \right\rangle = \left\{ {\begin{matrix}\begin{pmatrix}x \\y\end{pmatrix} & {x \geq y} \\0 & {x < y}\end{matrix},} \right.} & \left( {{Equation}\mspace{14mu} 2} \right)\end{matrix}$and compute the scalar r, which is given by:

$\begin{matrix}{r = {\sum\limits_{i = 0}^{m - 1}\;{\left\langle \begin{matrix}{n - s_{i}} \\{m - i}\end{matrix} \right\rangle.}}} & \left( {{Equation}\mspace{14mu} 3} \right)\end{matrix}$The range of r is given by:

$\begin{matrix}{r \in {\left\{ {0,\ldots\mspace{14mu},{\begin{pmatrix}n \\m\end{pmatrix} - 1}} \right\}.}} & \left( {{Equation}\mspace{14mu} 4} \right)\end{matrix}$Each value of r uniquely identifies which of the code words are inerror. Therefore, the code words that are in error can be representedusing q bits, where q is greater than or equal to:

$\begin{matrix}{{\log\; 2\left( {{}_{}^{}{}_{}^{}} \right)} = {{\log\; 2\left( \frac{n!}{{m!}{\left( {n - m} \right)!}} \right)} < n}} & \left( {{Equation}\mspace{14mu} 5} \right)\end{matrix}$

In one embodiment, as shown in FIG. 6, the ACK-NACK feedback 530includes two parts (Part-1 540 and Part-2 550). Part-1 540 includes pbits, which indicate the number of code words in error, while Part-2 550includes q bits, which indicate the particular code words that werereceived in error. In an exemplary embodiment, the p bits are stronglycoded to ensure they are received error-free, while the q bits areweakly coded to reduce bandwidth usage. In this embodiment, if thetransmitter is unable to decode the second part (q bits), thetransmitter can retransmit all code words in the transport block.

Exemplary bit patterns for the p bits in Part-1 540 of the ACK-NACKfeedback are shown in FIG. 7. In the embodiment shown in FIG. 7, Part-1540 of the ACK-NACK feedback includes two bits (p=2), which enables thereceiver to individually request retransmission of up to two code wordsreceived in error. If three or more code words are received in error,the transmitter will need to retransmit all of the code words in thetransport block. In the example shown in FIG. 7, if the receiverreceives all the code words without any error, the Part-1 feedback 540is set to {00}. If one of the code words is received in error, thePart-1 feedback 540 is set to {01}. If two code words are received inerror, the Part 1 feedback 540 is set to {10}. Otherwise, the Part-1feedback 540 is set to {11}, indicating that the transmitter has toretransmit all of the code words in the transport block.

The number of code words received in error should typically be less thanor equal to 2 due to the link adaptation scheduling. For example,typically, the link adaptation scheduling is done such that thetransport block's PER is approximately 10-20% (average of 15%). Assumingthe error pattern across code words is independent, with n code words,the per code word's error rate is approximately (15/n) %=(0.15/n).Therefore, with n code words, the average number of code words in erroris given by n*(0.15/n)=0.15. As a result, the number of code words inerror in a transport block is typically less than or equal to 2.

Referring now to FIGS. 6 and 7, with Part-1 540 including two bits, thenumber of bits in Part-2 (q bits) 550 is variable and can be derivedbased on number of code words in error and the total number of codewords in a transport block. This mapping can be decided up front betweentransmitter and receiver, as discussed above in connection with FIG. 5.The transmitter, based on the information decoded from Part-1 540, canthen determine q (size of Part-2 550), as well as the information inPart-2 550. For example, if the total number of code words is 4, q canbe set to 2 bits if the number of code words in error is 1, and can beset to 3 bits if the number of code words in error is 2. Regardless ofthe total number of code words, if the number of code words in error is0, then q can be set to 0 bits.

In an exemplary embodiment, when the number of code words within atransport block is less than or equal to 64, with Part-1 540 includingtwo bits, Part-2 550 can include 6 bits (q=6) to identify the particularcode word(s) received in error.

In an exemplary scenario, if the number of code words in a transportblock is less than or equal to 64 and greater than 11, and no code wordsare received in error, Part-1 540 can be set to {00}, while Part-2 550is not transmitted (or blank). If one code word is received in error,Part-1 540 can be set to {01}, and Part-2 550 can be appropriately setto indicate which code word was received in error. However, if more thanone code word is received in error, Part-1 540 can be set to {11}, whilePart-2 550 is not transmitted (or blank).

In another exemplary scenario, if the number of code words in atransport block is less than or equal to 11, and no code words arereceived in error, Part-1 540 can be set to {00}, while Part-2 550 isnot transmitted (or blank). If one code word is received in error,Part-1 540 can be set to IOU, and Part-2 550 can be appropriately set toindicate which code word was received in error. If two code words arereceived in error, Part-1 540 can be set to {10}, and Part-2 550 can beappropriately set to indicate which two code words were received inerror. However, if more than two code words are received in error,Part-1 540 can be set to {11}, while Part-2 550 is not transmitted (orblank).

As evident from the above scenarios, the maximum benefit occurs when thetotal number of code words in a transport block is less than or equal to11. In an LTE wireless communication system, 11 code words per transportblock corresponds to at least 4.2 bits/sec/Hz. In a fading environment,the SNR required to support such a spectral efficiency is approximately22 dB. Evidence has shown that at least 80% of wireless cellular networklocations/times experience an SNR less than or equal to 22 dB.Therefore, in at least 80% of locations and at least 80% of the time,the exemplary feedback mechanism discussed above is fully efficient.

It should be noted that in embodiments in which the number of code wordsin a transport block is greater than 64, the two-part ACK-NACK feedbackcan still be used. For example, if the number of code words in atransport block is greater than 64, and all code words were receivedwithout error at the receiver, Part-1 540 can be set to {00}, whilePart-2 550 is not transmitted (or blank). If at least one code word wasreceived in error, Part-1 540 can be set to {11}, indicating that allcode words in the transport block should be retransmitted, while Part-2550 is not transmitted (or blank).

It should be understood that the number of p bits 540 and q bits 550 isvariable, and embodiments of the present invention should not be limitedto any particular number of bits. In addition, it should be understoodthat the number of p bits 540 and q bits 550 can be predetermined, setduring the initial data scheduling between the transmitter and receiverand/or dynamically adjusted in real-time during a communication sessionbetween the transmitter and receiver based on network conditions orother factors.

Turning now to FIG. 8, in another embodiment, the ACK-NACK feedback 530sent from the receiver to the transmitter includes only q bits 550,which are used by the transmitter to determine which code words werereceived in error. For example, each code word can be represented by oneof the q bits to indicate whether that code word was received in erroror not. In an exemplary embodiment, the q bits 550 are strongly coded toensure that the bits are received at the transmitter without error toprevent packet loss. In another exemplary embodiment, the q bits 550 areweakly coded to utilize less bandwidth. However, in this embodiment, thepossibility of packet loss is greater.

FIG. 9 illustrates an exemplary ACK-NACK signaling method 900 accordingto embodiments of the present invention. At 910, an inbound RF signalcontaining a transport block of code words is received at a wirelessterminal. At 920, a determination is made whether any of the code wordswere received in error. If not, at 930, the wireless terminal transmitsback to the source of the RF signal an ACK-NACK message indicating thatall code words were received without error. If so, at 940, the wirelessterminal transmits back to the source of the RF signal an ACK-NACKmessage indicating the specific code words within the transport blockthat were received in error.

As may be used herein, the terms “substantially” and “approximately”provides an industry-accepted tolerance for its corresponding termand/or relativity between items. Such an industry-accepted toleranceranges from less than one percent to fifty percent and corresponds to,but is not limited to, component values, integrated circuit processvariations, temperature variations, rise and fall times, and/or thermalnoise. Such relativity between items ranges from a difference of a fewpercent to magnitude differences. As may also be used herein, theterm(s) “operably coupled to”, “coupled to”, and/or “coupling” includesdirect coupling between items and/or indirect coupling between items viaan intervening item (e.g., an item includes, but is not limited to, acomponent, an element, a circuit, and/or a module) where, for indirectcoupling, the intervening item does not modify the information of asignal but may adjust its current level, voltage level, and/or powerlevel. As may further be used herein, inferred coupling (i.e., where oneelement is coupled to another element by inference) includes direct andindirect coupling between two items in the same manner as “coupled to”.As may even further be used herein, the term “operable to” or “operablycoupled to” indicates that an item includes one or more of powerconnections, input(s), output(s), etc., to perform, when activated, oneor more its corresponding functions and may further include inferredcoupling to one or more other items. As may still further be usedherein, the term “associated with”, includes direct and/or indirectcoupling of separate items and/or one item being embedded within anotheritem. As may be used herein, the term “compares favorably”, indicatesthat a comparison between two or more items, signals, etc., provides adesired relationship. For example, when the desired relationship is thatsignal 1 has a greater magnitude than signal 2, a favorable comparisonmay be achieved when the magnitude of signal 1 is greater than that ofsignal 2 or when the magnitude of signal 2 is less than that of signal1.

As may also be used herein, the terms “processing module”, “module”,“processing circuit”, and/or “processing unit” (e.g., including variousmodules and/or circuitries such as may be operative, implemented, and/orfor encoding, for decoding, for baseband processing, etc.) may be asingle processing device or a plurality of processing devices. Such aprocessing device may be a microprocessor, micro-controller, digitalsignal processor, microcomputer, central processing unit, fieldprogrammable gate array, programmable logic device, state machine, logiccircuitry, analog circuitry, digital circuitry, and/or any device thatmanipulates signals (analog and/or digital) based on hard coding of thecircuitry and/or operational instructions. The processing module,module, processing circuit, and/or processing unit may have anassociated memory and/or an integrated memory element, which may be asingle memory device, a plurality of memory devices, and/or embeddedcircuitry of the processing module, module, processing circuit, and/orprocessing unit. Such a memory device may be a read-only memory (ROM),random access memory (RAM), volatile memory, non-volatile memory, staticmemory, dynamic memory, flash memory, cache memory, and/or any devicethat stores digital information. Note that if the processing module,module, processing circuit, and/or processing unit includes more thanone processing device, the processing devices may be centrally located(e.g., directly coupled together via a wired and/or wireless busstructure) or may be distributedly located (e.g., cloud computing viaindirect coupling via a local area network and/or a wide area network).Further note that if the processing module, module, processing circuit,and/or processing unit implements one or more of its functions via astate machine, analog circuitry, digital circuitry, and/or logiccircuitry, the memory and/or memory element storing the correspondingoperational instructions may be embedded within, or external to, thecircuitry comprising the state machine, analog circuitry, digitalcircuitry, and/or logic circuitry. Still further note that, the memoryelement may store, and the processing module, module, processingcircuit, and/or processing unit executes, hard coded and/or operationalinstructions corresponding to at least some of the steps and/orfunctions illustrated in one or more of the Figures. Such a memorydevice or memory element can be included in an article of manufacture.

The present invention has been described above with the aid of methodsteps illustrating the performance of specified functions andrelationships thereof. The boundaries and sequence of these functionalbuilding blocks and method steps have been arbitrarily defined hereinfor convenience of description. Alternate boundaries and sequences canbe defined so long as the specified functions and relationships areappropriately performed. Any such alternate boundaries or sequences arethus within the scope and spirit of the claimed invention. Further, theboundaries of these functional building blocks have been arbitrarilydefined for convenience of description. Alternate boundaries could bedefined as long as the certain significant functions are appropriatelyperformed. Similarly, flow diagram blocks may also have been arbitrarilydefined herein to illustrate certain significant functionality. To theextent used, the flow diagram block boundaries and sequence could havebeen defined otherwise and still perform the certain significantfunctionality. Such alternate definitions of both functional buildingblocks and flow diagram blocks and sequences are thus within the scopeand spirit of the claimed invention. One of average skill in the artwill also recognize that the functional building blocks, and otherillustrative blocks, modules and components herein, can be implementedas illustrated or by discrete components, application specificintegrated circuits, processors executing appropriate software and thelike or any combination thereof.

The present invention may have also been described, at least in part, interms of one or more embodiments. An embodiment of the present inventionis used herein to illustrate the present invention, an aspect thereof, afeature thereof, a concept thereof, and/or an example thereof. Aphysical embodiment of an apparatus, an article of manufacture, amachine, and/or of a process that embodies the present invention mayinclude one or more of the aspects, features, concepts, examples, etc.described with reference to one or more of the embodiments discussedherein. Further, from figure to figure, the embodiments may incorporatethe same or similarly named functions, steps, modules, etc. that may usethe same or different reference numbers and, as such, the functions,steps, modules, etc. may be the same or similar functions, steps,modules, etc. or different ones.

Unless specifically stated to the contrary, signals to, from, and/orbetween elements in a figure of any of the figures presented herein maybe analog or digital, continuous time or discrete time, and single-endedor differential. For instance, if a signal path is shown as asingle-ended path, it also represents a differential signal path.Similarly, if a signal path is shown as a differential path, it alsorepresents a single-ended signal path. While one or more particulararchitectures are described herein, other architectures can likewise beimplemented that use one or more data buses not expressly shown, directconnectivity between elements, and/or indirect coupling between otherelements as recognized by one of average skill in the art.

The term “module” is used in the description of the various embodimentsof the present invention. A module includes a functional block that isimplemented via hardware to perform one or module functions such as theprocessing of one or more input signals to produce one or more outputsignals. The hardware that implements the module may itself operate inconjunction software, and/or firmware. As used herein, a module maycontain one or more sub-modules that themselves are modules.

While particular combinations of various functions and features of thepresent invention have been expressly described herein, othercombinations of these features and functions are likewise possible. Thepresent invention is not limited by the particular examples disclosedherein and expressly incorporates these other combinations.

What is claimed is:
 1. An apparatus, comprising: a transmitterconfigured to transmit an outbound Radio Frequency (RF)signal to adestination device, the outbound RF signal including a plurality of codewords forming a transport block; a receiver configured to receive anAcknowledgement-Negative Acknowledgement (ACK-NACK) message from thedestination device, wherein when one or more of the code words withinthe transport block were received in error by the destination device,the ACK-NACK message indicating the one or more of the code words thatwere received in error; and a processing module configured to determinethe one or more of the code words that were received in error from theACK-NACK message and retransmit the one or more of the code words thatwere received in error to the destination device via the transmitter. 2.The apparatus of claim 1, wherein the ACK-NACK message includes a firstpart indicating a number of code words received in error and a secondpart indicating the one or more of the code words that were received inerror.
 3. The apparatus of claim 2, wherein bits in the first part arecoded more strongly than bits in the second part.
 4. The apparatus ofclaim 2, wherein a number of bits in at least one of the first part andthe second part is variable based on a number of code words in thetransport block and the number of code words received in error.
 5. Theapparatus of claim 4, wherein the number of bits in at least one of thefirst part and the second part is dynamically adjusted in real-time. 6.The apparatus of claim 2, wherein a number of bits in the first part istwo.
 7. The apparatus of claim 6, wherein a number of bits in the secondpart is zero when one or more of all of the code words in the transportblock were received without error or more than two code words arereceived in error.
 8. The apparatus of claim 6, wherein a number of bitsin the second part is six when at least one of the code words isreceived in error.
 9. The apparatus of claim 1, wherein the ACK-NACKmessage includes one bit for each code word in the transport block. 10.The apparatus of claim 1, wherein the processing module is furtherconfigured to determine a format of the ACK-NACK message to be used bythe destination device and to transmit control information including theformat of the ACK-NACK message to the destination device via thetransmitter.
 11. An apparatus, comprising: a transmitter configured totransmit an outbound Radio Frequency (RF) signal to a destinationdevice, the outbound RF signal including a plurality of code wordsforming a transport block; a receiver configured to receive anAcknowledgement-Negative Acknowledgement (ACK-NACK) message from thedestination device, the ACK-NACK message having a variable format basedon a number of code words in the transport block and a number of codewords received in error by the destination device, wherein when one ormore of the code words within the transport block were received in errorby the destination device, the ACK-NACK message indicating the one ormore of the code words that were received in error; and a processingmodule configured to determine the one or more of the code words thatwere received in error from the ACK-NACK message and retransmit the oneor more of the code words that were received in error to the destinationdevice via the transmitter.
 12. The apparatus of claim 11, wherein theACK-NACK message includes a first part indicating the number of codewords received in error and a second part indicating the one or more ofthe code words that were received in error.
 13. The apparatus of claim12, wherein bits in the first part are coded more strongly than bits inthe second part.
 14. The apparatus of claim 12, wherein a number of bitsin at least one of the first part and the second part is variable basedon the number of code words in the transport block and the number ofcode words received in error.
 15. The apparatus of claim 14, wherein thenumber of bits in at least one of the first part and the second part isdynamically adjusted in real-time.
 16. The apparatus of claim 12,wherein a number of bits in the first part is two.
 17. The apparatus ofclaim 16, wherein a number of bits in the second part is zero when oneor more of all of the code words in the transport block were receivedwithout error or more than two code words are received in error.
 18. Theapparatus of claim 16, wherein a number of bits in the second part issix when at least one of the code words is received in error.
 19. Amethod for Acknowledgement-Negative Acknowledgement (ACK-NACK)signaling, comprising: transmitting an outbound Radio Frequency (RF)signal to a destination device, the outbound RF signal including aplurality of code words forming a transport block; receiving anAcknowledgement-Negative Acknowledgement (ACK-NACK) message from thedestination device, wherein when one or more of the code words withinthe transport block were received in error by the destination device,the ACK-NACK message indicating the one or more of the code words thatwere received in error; determining the one or more of the code wordsthat were received in error from the ACK-NACK message; andretransmitting the one or more of the code words that were received inerror to the destination device.
 20. The method of claim 19, wherein theACK-NACK message includes a first part indicating a number of code wordsreceived in error and a second part indicating the one or more of thecode words that were received in error, a number of bits in at least oneof the first part and the second part being variable based on a numberof code words in the transport block and the number of code wordsreceived in error.